Blizzard in Alaska, November 13, 2012

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
326 PM AKST MON NOV 12 2012

.DISCUSSION...
DYNAMIC WEATHER PATTERN FOR NORTHERN ALASKA OVER THE NEXT COUPLE
OF DAYS. 958MB LOW SW OF ADAK MON AFTERNOON WILL ONLY SLOWLY WEAKEN
AS IT MOVES TO NEAR ST PAUL ISLAND BY TUE EVENING. THE ASSOCIATED
OCCLUSION IS FRACTURED AND WILL INCREASINGLY BE SHEARED APART AS
MOST OF THE DYNAMICS PROPAGATE EWD INTO THE GULF OF ALASKA.
MEANWHILE...990MB LOW NEAR 80N/120W HAS A STRONG COLD FRONT THAT
WILL MOVE ACROSS THE THE NORTH SLOPE MON NIGHT EVEN AS LOW MOVES
SWD. THE ASSOCIATED DIGGING TROF WILL NOT ONLY KEEP A COOL PATTERN
IN PLACE OVER MUCH OF THE INTERIOR BUT IS THE FORCING PREVENTING
THE BERING SEA LOW FROM MOVING NORTH OF 60N. SFC HIGH
CURRENTLY STRETCHES FROM NRN CHUKOTKA EWD ACROSS NRN INTERIOR
ALASKA WILL BASICALLY PERSIST BUT RECENTER OVER THE BROOKS RANGE
AS CRCLN FROM BERING THEN GULF OF ALASKA LOWS EXPANDS NORTH OF
THE ALASKA RANGE.

THE MODEL GUIDANCE HAS SOME VARIANCE IN HOW MUCH WX WILL BE LEFT
IN THE OCCLUSION AS IT MOVES NEWD. HOWEVER...THERE DOES SEEM TO BE
AGREEMENT THAT THERE WILL BE LITTLE OR NO FREEZING RAIN NORTH OF
THE KUSKO RIVER ZONES AND QPFS WILL LIKELY REMAIN BLO HALF AN
INCH. WITH IN CLOUD TEMPS UP ABOUT -5C AND FAIRLY STRONG SFC WINDS
RESULTING IN CRYSTAL FRACTURING...SNOW-LIQUID RATIOS SHOULD BE
NEAR 10-1.

MID-RANGE GUIDANCE IS ACTUALLY FAIRLY CONSISTENT...WITH RIDGE
ALONG ABOUT THE DATELINE DRIFTING EWD A BIT AND LONG WAVE
TROUGHING ALONG ABOUT 135W. THIS WILL BE A COOL AND MOSTLY DRY
PATTERN FOR THE CWA...WITH ERN ZONES HAVING LARGER NEGATIVE TEMP
ANOMALIES THAN THE WEST COAST.

NORTH SLOPE...NO CHANGE FROM THE PREVIOUS FORECAST PACKAGE
WITH THE WARNINGS. BLIZZARD STARTING THIS EVENING SEEMS A NEAR
CERTAINTY FOR ZONE 204...WITH COLD ADVECTION...STRONG LOW LEVEL
WINDS AND A NWLY PRES GRADIENT TO ENHANCE THE BARRIER JET. BLIZ IS
LIKELY IN ZONE 203 AS WELL BUT WINDS NOT AS STRONG AND WILL NOT
LAST AS LONG.

WEST COAST...WITH THE OCCLUSION WKNG QUICKLY AS IT MOVES
NWD...THERE SEEMS TO BE ALMOST NO WINTER WEATHER ELEMENT THAT
COULD REACH WARNING CRITERIA. IT IS POSSIBLE THAT IN ZONE 215
EITHER SNOW OR FREEING RAIN MIGHT MAKE ADVISORY LEVEL AND THIS
WILL HAVE TO BE WATCHED.

INTERIOR...IN THE SHORT TERM MAIN FORECAST PROBLEM IS PATCHY BUT
SLOWLY DECREASING STRATUS AND THE IMPACTS OF 20+ DEGREES ON VALLEY
TEMPS. WINDS WILL INCREASE MID-WEEK AS LOW IN THE GULF EXPANDS.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
BLIZZARD WARNING FOR AKZ203-AKZ204.

HEAVY FREEZING SPRAY WARNING FOR PKZ210-PKZ220-PKZ225-PKZ230-
PKZ245.

GALE WARNING FOR PKZ200-PKZ210-PKZ240-PKZ245.

STORM WARNING FOR PKZ210.

SMALL CRAFT ADVISORY FOR PKZ220-PKZ230.

BRISK WIND ADVISORY FOR PKZ200-PKZ235-PKZ240.
&&

RT NOV 12